diff options
| -rw-r--r-- | block.c | 112 |
1 files changed, 62 insertions, 50 deletions
@@ -44,6 +44,8 @@ #include <windows.h> #endif +#define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ + static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load); static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, @@ -74,6 +76,8 @@ static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, static int coroutine_fn bdrv_co_flush_em(BlockDriverState *bs); static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); +static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); static QTAILQ_HEAD(, BlockDriverState) bdrv_states = QTAILQ_HEAD_INITIALIZER(bdrv_states); @@ -1042,30 +1046,69 @@ static inline bool bdrv_has_async_flush(BlockDriver *drv) return drv->bdrv_aio_flush != bdrv_aio_flush_em; } -/* return < 0 if error. See bdrv_write() for the return codes */ -int bdrv_read(BlockDriverState *bs, int64_t sector_num, - uint8_t *buf, int nb_sectors) +typedef struct RwCo { + BlockDriverState *bs; + int64_t sector_num; + int nb_sectors; + QEMUIOVector *qiov; + bool is_write; + int ret; +} RwCo; + +static void coroutine_fn bdrv_rw_co_entry(void *opaque) { - BlockDriver *drv = bs->drv; + RwCo *rwco = opaque; - if (!drv) - return -ENOMEDIUM; + if (!rwco->is_write) { + rwco->ret = bdrv_co_do_readv(rwco->bs, rwco->sector_num, + rwco->nb_sectors, rwco->qiov); + } else { + rwco->ret = bdrv_co_do_writev(rwco->bs, rwco->sector_num, + rwco->nb_sectors, rwco->qiov); + } +} - if (bdrv_has_async_rw(drv) && qemu_in_coroutine()) { - QEMUIOVector qiov; - struct iovec iov = { - .iov_base = (void *)buf, - .iov_len = nb_sectors * BDRV_SECTOR_SIZE, - }; +/* + * Process a synchronous request using coroutines + */ +static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, + int nb_sectors, bool is_write) +{ + QEMUIOVector qiov; + struct iovec iov = { + .iov_base = (void *)buf, + .iov_len = nb_sectors * BDRV_SECTOR_SIZE, + }; + Coroutine *co; + RwCo rwco = { + .bs = bs, + .sector_num = sector_num, + .nb_sectors = nb_sectors, + .qiov = &qiov, + .is_write = is_write, + .ret = NOT_DONE, + }; - qemu_iovec_init_external(&qiov, &iov, 1); - return bdrv_co_readv(bs, sector_num, nb_sectors, &qiov); - } + qemu_iovec_init_external(&qiov, &iov, 1); - if (bdrv_check_request(bs, sector_num, nb_sectors)) - return -EIO; + if (qemu_in_coroutine()) { + /* Fast-path if already in coroutine context */ + bdrv_rw_co_entry(&rwco); + } else { + co = qemu_coroutine_create(bdrv_rw_co_entry); + qemu_coroutine_enter(co, &rwco); + while (rwco.ret == NOT_DONE) { + qemu_aio_wait(); + } + } + return rwco.ret; +} - return drv->bdrv_read(bs, sector_num, buf, nb_sectors); +/* return < 0 if error. See bdrv_write() for the return codes */ +int bdrv_read(BlockDriverState *bs, int64_t sector_num, + uint8_t *buf, int nb_sectors) +{ + return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false); } static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num, @@ -1105,36 +1148,7 @@ static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num, int bdrv_write(BlockDriverState *bs, int64_t sector_num, const uint8_t *buf, int nb_sectors) { - BlockDriver *drv = bs->drv; - - if (!bs->drv) - return -ENOMEDIUM; - - if (bdrv_has_async_rw(drv) && qemu_in_coroutine()) { - QEMUIOVector qiov; - struct iovec iov = { - .iov_base = (void *)buf, - .iov_len = nb_sectors * BDRV_SECTOR_SIZE, - }; - - qemu_iovec_init_external(&qiov, &iov, 1); - return bdrv_co_writev(bs, sector_num, nb_sectors, &qiov); - } - - if (bs->read_only) - return -EACCES; - if (bdrv_check_request(bs, sector_num, nb_sectors)) - return -EIO; - - if (bs->dirty_bitmap) { - set_dirty_bitmap(bs, sector_num, nb_sectors, 1); - } - - if (bs->wr_highest_sector < sector_num + nb_sectors - 1) { - bs->wr_highest_sector = sector_num + nb_sectors - 1; - } - - return drv->bdrv_write(bs, sector_num, buf, nb_sectors); + return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true); } int bdrv_pread(BlockDriverState *bs, int64_t offset, @@ -2912,8 +2926,6 @@ static void bdrv_rw_em_cb(void *opaque, int ret) *(int *)opaque = ret; } -#define NOT_DONE 0x7fffffff - static int bdrv_read_em(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors) { |